compounding HOTLINE

JULY 01, 2006

Martin A. Erickson III, RPh

Q

We have a dispute in the pharmacy about beyond-use
dating (BUD) of topical preparations where no stability
information is available. One of us thinks that the
creams and ointments are solids and therefore must be
assigned BUD of 6 months when a United States Pharmacopeia
(USP) or National Formulary bulk powder is the source of the
active ingredient. Another of us wants to assign 14 days, based
on the presence of water. Can you help clarify?

A

USP 29<795>, Pharmaceutical CompoundingNonsterile Preparations, provides guidance for assigning
BUD where no stability information specific to the
formulation is available. When reading this material and contemplating
the assignment of such dating, it is important for
us as pharmacists to use professional judgment. It also is helpful
to refer to reliable sources for background information
when considering apparent conflicts within a particular scientific
report, official guidance, or official compendium.

Reportedly, 3 factors to consider when evaluating the length
of time a drug dose form might be considered "available" to
the patient are temperature, moisture, and pH. Generally,
excessive moisture shortens the "life" of a dose form by causing
physical effects such as capsule gelatin degradation and
"clumping" of ingredients, and also chemical degradation
when the drug is in solution (suspensions might reasonably be
included). In both cases, the term excessive is relative to the
situation.

Additionally, a helpful "decision tree" was published in the
International Journal of Pharmaceutical Compounding
(Standard operating procedure: assignment of a beyond-use
date for compounded preparations. IJPC. 4[6]:474-475).

The "tree"provides a "process of elimination" for assigning
a BUD, beginning with a decision as to whether a preparation
is a "solid." In the case you mention (creamspharmaceutically
defined as ointments) are at best semi-solid. The tree
then leads to a decision as to whether the preparation is a liquidwhich it clearly is not. Therefore, ointments and creams
fall into the "All other dosage forms" category and might reasonably
be assigned BUD "not later than the intended duration
of therapy or 30 days, whichever is earlier." [USP 29 <795>]